Re: [PATCH] platform/x86: thinkpad_acpi: Fix NULL pointer dereferences while probing

From: Genes Lists <lists@sapience.com>
To: "Kurt Borja" <kuurtb@gmail.com>,
	"Henrique de Moraes Holschuh" <hmh@hmh.eng.br>,
	"Hans de Goede" <hdegoede@redhat.com>,
	"Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>,
	"Mark Pearson" <mpearson-lenovo@squebb.ca>
Cc: ibm-acpi-devel@lists.sourceforge.net,
	platform-driver-x86@vger.kernel.org,
		linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
	Damian Tometzki	 <damian@riscv-rocks.de>
Subject: Re: [PATCH] platform/x86: thinkpad_acpi: Fix NULL pointer dereferences while probing
Date: Mon, 31 Mar 2025 13:26:51 -0400	[thread overview]
Message-ID: <b508c090dced250a32f413f9ce0d65fd6457f832.camel@sapience.com> (raw)
In-Reply-To: <20250330-thinkpad-fix-v1-1-4906b3fe6b74@gmail.com>


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On Sun, 2025-03-30 at 12:39 -0300, Kurt Borja wrote:
> Some subdrivers make use of the global reference tpacpi_pdev during
> initialization, which is called from the platform driver's probe.
> However, after
> 
> commit 38b9ab80db31 ("platform/x86: thinkpad_acpi: Move subdriver
> initialization to tpacpi_pdriver's probe.")
> 
> this variable is only properly initialized *after* probing and this
> can
> result in a NULL pointer dereference.
> 
> In order to fix this without reverting the commit, register the
> platform
> bundle in two steps, first create and initialize tpacpi_pdev, then
> register the driver synchronously with platform_driver_probe(). This
> way
> the benefits of commit 38b9ab80db31 are preserved.
> 
> Additionally,
> 
> commit 43fc63a1e8f6 ("platform/x86: thinkpad_acpi: Move HWMON
> initialization to tpacpi_hwmon_pdriver's probe")
> 
> introduced a similar problem, however tpacpi_sensors_pdev is only
> used
> once inside the probe, so replace the global reference with the one
> given by the probe.
> 
> ...
> base-commit: 1a9239bb4253f9076b5b4b2a1a4e8d7defd77a95
> change-id: 20250330-thinkpad-fix-98db0d8c3be3
> 
Fixed problem seen here on thinkpad.
Tested on mainline commit 4e82c87058f45e79eeaa4d5bcc3b38dd3dce7209

Tested-by: Gene C <arch@sapience.com>


-- 
Gene

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